The Internet of Things (IoT) introduces objects or things to Human-to-Human (H2H) based Internet services. It marks a stage of the Internet where physical or virtual objects are interconnected to enable the Internet of Services (IoS). Many of these services are proximity based, such as smart shopping, smart home, smart office, smart health, smart transportation, smart parking, smart grid, and smart city, among other things. Peer-to-peer (P2P) communications may need to be considered in an IoT environment. Examples of P2P communication use include:                Connection—Social Networking (SN) and Internet of Things (IoT): pair or group connections, statuses updates, keep alive, etc.        Advertisement: broadcast, group-cast, or unicast—personalized advertising, etc.        User Centric Activities at Proximity: pair or group based gaming, streaming, content exchanging, etc.        Smart Environment: home/office device control—auto configuration, synchronization, update, etc.        Health: peer monitoring and assistance, medical and hospital services, etc.        Security and Safety: hazard alarms, emergency alarms, police or public safety services, etc.        Smart Transportation: congestion, accident or event notification; interactive transportation management—car pooling, train scheduling, traffic control, airplane ticket updates, etc.        Network of Network: multi-hop to infrastructure; offloading from infrastructure; up loading to hot spot, etc.        
Peer-to-peer (P2P) communication, as further described herein, may be centralized with a central controller for the infrastructure-based or fully distributed system without a central controller for the infrastructure-less. Example of P2P devices may include a tablet, smart phone, music player, game console, personal digital assistance, laptop, personal computer (PC), medical device, connected car, smart meter, home gateway, monitor, alarm, set-top box, or printer, among other things. Some standards have identified P2P communication use inside their standardization scope. For example, IEEE 802.15.8 aims to specify PHY and MAC protocols for fully distributed peer-aware communications to support services such as social networking, advertising, gaming, streaming, and emergency services.
IEEE 802.15.8 features, as discussed in IEEE 802.15 Peer Aware Communications (PAC) Study Group (SG) 5 Criteria, may include discovery for peer information without association. A typical discovery signaling rate may be greater than 100 kbps and the number of devices in the discovery may be more than 100 devices. PAC may also scalable data transmission rates (e.g., 10 Mbps), group communications with simultaneous membership in multiple groups (e.g., up to 10), relative positioning, multi-hop relay and security. PAC may be operational in selected globally available unlicensed/licensed bands below 11 GHz capable of supporting certain requirements.
In P2P communication, there may be different frame structures used based on the implementation. For example, IEEE 802 has the following types of frame structures. FIG. 1 illustrates the alternation between the contention free period (CFP) and contention period (CP) in IEEE 802.11 and 802.15 systems, which starts with a beacon 101, followed by CP 102 and CFP 103. Point coordination function (PCF) is used during CFP 103, and distributed coordination function (DCF) is used during CP 102.
FIG. 2 illustrates an example of a general superframe structure in IEEE 802.15.4. The general superframe in IEEE 802.15.4 consists of contention period and contention free period. Contention free period is pre-allocated to specific users. The allocation is determined within CAP 105. The general superframe in 802.15.4 consists of contention period 105 and contention free period 106. Table 1 summarizes a set of frame structures defined in IEEE 802.15.4 standard family.
TABLE 1Frame Structures Defined in 802.15.4 Standard FamilyFrame StructureStandardGeneral Superframe shown in FIG. 2802.15.4-2011LLDN (Low Latency Deterministic802.15.4e-2011 (IEEE 802.15.4e,Network) Superframe shown inDraft IEEE P802_15_4e-D8.0)FIG. 3DSME (Deterministic and802.15.4e-2011 (IEEE 802.15.4e,Synchronous Multi-channelDraft IEEE P802_15_4e-D8.0)Extension) Multi-superframe shownin FIG. 4TMCTP Superframe (TVWS802.15.4m-2013 (IEEEmultichannel cluster tree PAN)802.15.4m/D0-2013, PHY/MACshown in FIG. 5Amendment for TV White SpaceBetween 54 MHz and 862 MHzPhysical Layer)